src/cobalt/renderer/rasterizer/egl/draw_object_manager.h

// Copyright 2017 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef COBALT_RENDERER_RASTERIZER_EGL_DRAW_OBJECT_MANAGER_H_
#define COBALT_RENDERER_RASTERIZER_EGL_DRAW_OBJECT_MANAGER_H_

#include <vector>

#include "base/memory/scoped_ptr.h"
#include "base/memory/scoped_vector.h"
#include "cobalt/math/rect_f.h"
#include "cobalt/renderer/rasterizer/egl/draw_object.h"
#include "cobalt/renderer/rasterizer/egl/graphics_state.h"
#include "cobalt/renderer/rasterizer/egl/shader_program_manager.h"

namespace cobalt {
namespace renderer {
namespace rasterizer {
namespace egl {

// Helper class to manage a set of draw objects. This facilitates sorting the
// objects to minimize GPU state changes.
class DrawObjectManager {
 public:
  enum OnscreenType {
    kOnscreenRectTexture = 0,
    kOnscreenRectColorTexture,
    kOnscreenPolyColor,
    kOnscreenTransparent,
    kOnscreenCount,
  };

  // Order offscreen rendering by descending expected pixel area. This helps
  // make better use of the offscreen texture atlas as smaller requests can
  // fill in gaps created by the larger requests.
  enum OffscreenType {
    kOffscreenSkiaFilter = 0,
    kOffscreenSkiaShadow,
    kOffscreenSkiaMultiPlaneImage,
    kOffscreenSkiaRectRounded,
    kOffscreenSkiaRectBrush,
    kOffscreenSkiaRectBorder,
    kOffscreenSkiaText,
    kOffscreenCount,
    kOffscreenNone,     // ExecuteOffscreenRasterize will not be run for these.
  };

  void AddOpaqueDraw(scoped_ptr<DrawObject> object,
                     OnscreenType onscreen_type,
                     OffscreenType offscreen_type);
  void AddTransparentDraw(scoped_ptr<DrawObject> object,
                          OnscreenType onscreen_type,
                          OffscreenType offscreen_type,
                          const math::RectF& bounds);

  void ExecuteOffscreenRasterize(GraphicsState* graphics_state,
      ShaderProgramManager* program_manager);
  void ExecuteOnscreenUpdateVertexBuffer(GraphicsState* graphics_state,
      ShaderProgramManager* program_manager);
  void ExecuteOnscreenRasterize(GraphicsState* graphics_state,
      ShaderProgramManager* program_manager);

 private:
  struct TransparentObjectInfo {
    TransparentObjectInfo(OnscreenType onscreen_type,
                          const math::RectF& object_bounds)
        : bounds(object_bounds),
          type(onscreen_type) {}
    math::RectF bounds;
    OnscreenType type;
  };

  ScopedVector<DrawObject> draw_objects_[kOnscreenCount];
  std::vector<TransparentObjectInfo> transparent_object_info_;

  // Manage execution order of objects in the draw_objects_ vectors. This does
  // not manage destruction of objects.
  std::vector<DrawObject*> offscreen_order_[kOffscreenCount];
};

}  // namespace egl
}  // namespace rasterizer
}  // namespace renderer
}  // namespace cobalt

#endif  // COBALT_RENDERER_RASTERIZER_EGL_DRAW_OBJECT_MANAGER_H_